The types of brush cleaning of a semiconductor wafer include roll-brush cleaning and pen-brush cleaning (sweep-brush cleaning). In the roll-brush cleaning, the wafer is cleaned by sandwiching the wafer by brushes having roll shapes from both faces of the wafer, and rotating the wafer and the brushes. In the pen-brush cleaning, the wafer is cleaned by bringing a brush having a pen shape into contact with a face of the wafer, and sweeping the face of the wafer by the brush while rotating the wafer and the brush.
The pen-brush cleaning has an advantage that the rotating speed of the wafer can be easily increased. Therefore, in the pen-brush cleaning, the relative speed of the wafer and the brush upon cleaning can be increased compared with the roll-brush cleaning, and the cleaning performance of the wafer can be increased.
However, the pen-brush cleaning has the following problems. In order to rotate the wafer at high speed in the pen-brush cleaning, the wafer has to be chucked by chuck pins in the vicinities of the circumference of the wafer. However, if the brush and a chuck pin contact each other, the brush may fall or the rotation of the wafer may be stopped. Therefore, the wafer cannot be cleaned to the circumference, and the brush has to be pulled up at a wafer circumferential portion in the vicinity of the circumference after the cleaning is finished. Therefore, there are problems that foreign matters remain on the wafer circumferential portion and the foreign matters attached to the brush are reattached to the wafer upon pull-up of the brush.